Megatest

;; used and to shutdown after sometime if it is not.
;;
(define (http-transport:keep-running) 
  ;; if none running or if > 20 seconds since 
  ;; server last used then start shutdown
  ;; This thread waits for the server to come alive
  (debug:print-info 0 *default-log-port* "Starting the sync-back, keep alive thread in server")

  (let* ((sdat              #f)
	 (no-sync-db        (db:open-no-sync-db))
	 (tmp-area          (common:get-db-tmp-area))
	 (started-file      (conc tmp-area "/.server-started"))
	 (server-start-time (current-seconds))
	 (server-info (let loop ((start-time (current-seconds))
				 (changed    #t)
				 (last-sdat  "not this"))
                        (begin ;; let ((sdat #f))
			  (thread-sleep! 0.01)
			  (debug:print-info 0 *default-log-port* "Waiting for server alive signature")
                          (mutex-lock! *heartbeat-mutex*)
                          (set! sdat *server-info*)
                          (mutex-unlock! *heartbeat-mutex*)
                          (if (and sdat
				   (not changed)
				   (> (- (current-seconds) start-time) 2))
			      (let* ((servinfodir (conc *toppath*"/.servinfo"))
				     (ipaddr      (car sdat))
				     (port        (cadr sdat))
				     (servinf     (conc servinfodir"/"ipaddr":"port)))

				(if (not (file-exists? servinfodir))
				    (create-directory servinfodir #t))
				(with-output-to-file servinf
				  (lambda ()
				    (let* ((serv-id (server:mk-signature)))
				      (set! *server-id* serv-id)
				      (print "SERVER STARTED: "ipaddr":"port" AT "(current-seconds)" server-id: "serv-id" pid: "(current-process-id))

      ;; Use this opportunity to sync the tmp db to megatest.db
      (if (not server-going) ;; *dbstruct-dbs* 
	  (begin
	    (debug:print 0 *default-log-port* "SERVER: dbprep")
	    (set! *dbstruct-dbs*  (db:setup #t)) ;;  run-id)) FIXME!!!
	    (set! server-going #t)
	    (debug:print 0 *default-log-port* "SERVER: running, megatest version: " (common:get-full-version)) ;; NOTE: the server is NOT yet marked as running in the log. We do that in the keep-running routine.

	    ;; (thread-start! *watchdog*)
          ) 
	  (if (and no-sync-db
		   (common:low-noise-print 5 "sync-all")) ;; cheesy way to reduce frequency of running sync :)
              (begin
                (debug:print 0 *default-log-port* "keep-running calling db:all-db-sync at " (time->string (seconds->local-time) "%H:%M:%S"))

		;; This is tougher than it seems - have to deal with multiple dbs
		;; (db:process-transaction-queue *dbstruct-dbs*)

		(db:all-db-sync *dbstruct-dbs*)
		
                ;; (db:do-sync no-sync-db)
	        ;; (db:run-lock-and-sync *no-sync-db*)
              )
          )
      )
      
      ;; when things go wrong we don't want to be doing the various queries too often
      ;; so we strive to run this stuff only every four seconds or so.
      (let* ((sync-time (- (current-milliseconds) start-time))
	    (rem-time  (quotient (- 4000 sync-time) 1000)))
	(if (and (<= rem-time 4)
		 (>  rem-time 0))

	     (flush-output *default-log-port*)))
      (if (common:low-noise-print 60 "dbstats")
	  (begin
	    (debug:print 0 *default-log-port* "Server stats:")
	    (db:print-current-query-stats)))
      (let* ((hrs-since-start  (/ (- (current-seconds) server-start-time) 3600)))
	(cond
	 #;((and *server-run*
	       (> (- (current-seconds) server-start-time) 420)) ;; let's try server replacement
	  ;; ((adj-proc-load . 0.056875) (adj-core-load . 0.11375) (1m-load . 0.91) (5m-load . 0.77) (15m-load . 1.0) (proc . 16) (core . 8) (phys . 1))
	  (let* ((loaddat       (common:get-normalized-cpu-load #f))
		 (adj-proc-load (alist-ref 'adj-proc-load loaddat))
		 (adj-core-load (alist-ref 'adj-core-load loaddat))
		 (adj-load      (max adj-proc-load adj-core-load)))
	    (if (< adj-load 2) ;; reduce chance of runaway
		(server:run *toppath*))
	    (db:all-db-sync *dbstruct-dbs*)
	    (thread-sleep! 30)
	    (http-transport:server-shutdown port)))
         ((and *server-run*
	       (> (+ last-access server-timeout)
		  (current-seconds)))
          (if (common:low-noise-print 120 "server continuing")
              (debug:print-info 0 *default-log-port* "Server continuing, seconds since last db access: " (- (current-seconds) last-access))
	      (let ((curr-time (current-seconds)))
		(handle-exceptions
		    exn
		    (debug:print 0 *default-log-port* "ERROR: Failed to change timestamp on log file " server-log-file ". Are you out of space on that disk? exn=" exn)
		    (if (and (< (- (current-seconds) server-start-time) 600) ;; run for ten minutes for experiment, 3600 thereafter
			     (not *server-overloaded*))
			(change-file-times server-log-file curr-time curr-time)
			(if (common:low-noise-print 120 "start new server")



			    (server:kind-run *toppath*) ;; server:kind-run uses [servers] numservers
			)))))
          (loop 0 server-state bad-sync-count (current-milliseconds)))
         (else
          (debug:print-info 0 *default-log-port* "Server timed out. seconds since last db access: " (- (current-seconds) last-access))
          (http-transport:server-shutdown port)))))))

(define (http-transport:server-shutdown port)
  (begin

	    ((homehost) (cons host (am-home?))) ;; shut up old code
	    ((home?)    (am-home?))
	    ((best-five)(names->dats (best-five)))
	    ((all-valid)(names->dats all-valid))
	    ((best)     (let* ((best-five (best-five))
			       (len       (length best-five)))
			  (hash-table-ref serversdat (list-ref best-five (random len)))))
			  
	    (else
	     (debug:print 0 *default-log-port* "ERROR: invalid command "mode)
	     #f)))
	(begin
	  (server:run areapath)
	  (thread-sleep! 3)
	  (case mode

;; kind start up of server, wait before allowing another server for a given
;; area to be launched
;;
(define (server:kind-run areapath)
  ;; look for $MT_RUN_AREA_HOME/logs/server-start-last
  ;; and wait for it to be at least <server idletime> seconds old
  ;; (server:wait-for-server-start-last-flag areapath)

  (server:run areapath)
  #;(if (not (server:check-if-running areapath)) ;; why try if there is already a server running?
      (let* ((lock-file    (conc areapath "/logs/server-start.lock")))
	(let* ((start-flag (conc areapath "/logs/server-start-last")))
	  (common:simple-file-lock-and-wait lock-file expire-time: 25)
	  (debug:print-info  2 *default-log-port* "server:kind-run: touching " start-flag)
	  (system (conc "touch " start-flag)) ;; lazy but safe
	  (server:run areapath)